1. Field of the Invention
The present invention generally relates to topical sarcoidosis and, more particularly, is concerned with a method employing an imiquimod cream for the treatment of topical sarcoidosis on equine.
2. Description of the Prior Art
Sarcoidosis is an ailment of equine, such as horses, donkeys and mules. Sarcoidosis is most commonly topical in nature. Sarcoids are the typical symptomatic manifestations of sarcoidosis. Sarcoids are tumors which are nonmetastatic. Sarcoids are formed by proliferation of neoplastic fibroblasts which results in the thickening or ulceration of skin. Sarcoids may occur alone or in clusters. Sarcoids commonly arise on the head, limbs and abdomen, but can occur anywhere on the body of a horse. Sarcoids are the most frequently found tumor of horses. Though not life threatening, sarcoids generally reduce the value of a horse because their location on the horse adversely affects the performance of the horse when employed for various activities. Sarcoidosis is believed to be caused by infection of the bovine papilloma virus.
A variety of treatments for topical sarcoidosis have been tried over the years, including surgical excision, cryotherapy, immunotherapy, radiotherapy, laser therapy, hyperthermia and topical and intratumoral chemotherapy. Surgical excision involves the use of surgical techniques to cut and remove sarcoids from adjacent healthy tissue. Cryotherapy involves freezing sarcoids. A refrigerant, commonly liquid nitrogen, is sprayed on the sarcoids to kill the cells of the tumors. Immunotherapy involves the use of antigens to stimulate lymphocytes and to increase natural killer cells of the host animal to kill the cells of the sarcoids. An attenuated strain of Mycobacterium bovis is commonly used in this procedure. Radiotherapy involves the use of radiation to kill the cells of the sarcoids. Radioactive isotopes are used to deliver a continuous and high dose of radiation locally to each tumor without affecting adjacent healthy tissue. Laser therapy involves cutting and evaporating sarcoids with a laser. Carbon dioxide lasers are commonly used for this procedure. Hyperthermia involves heating the tumor cells to kill them. The hyperthermia is commonly induced by a radio-frequency current. Topical chemotherapy involves topical applications of caustic or antimetabolite drugs to kill sarcoid cells. Podophyllum and 5-fluorouracil are commonly used for this procedure. Intratumoral chemotherapy involves the use of implants of caustic or antimetabolite drugs within the sarcoids to kill the cells of the tumors. Cisplatin and 5-fluorouracil are commonly used in the implants.
Each of these prior art methods of treatment for topical sarcoidosis appears to be somewhat satisfactory to varying degrees. However, many of the treatments have adverse side effects or risks, none of the treatments are universally effective in eliminating or reducing sarcoids and new sarcoids frequently recur following each of the treatments and additional treatments are required. Thus, a need remains for a more effective solution in treating topical sarcoidosis on equine without introducing any new problems in place of the aforementioned problems of the prior art treatments.
Imiquimod cream has been used to treat ailments of humans. Imiquimod is an immune-response modifier which is capable of inducing cytokines, including interferon alfa, tumor necrosis factor-a and interleukins 1, 6 and 8. An imiquimod 5% cream, developed by 3M Pharmaceuticals of St. Paul, Minn., and manufactured and marketed under the trademark "Aldara," has been used to treat genital warts of humans. Unlike sarcoids, genital warts are primarily sexually transmitted and caused by the human papilloma virus and the warts of this human disease are found only in the genital and perianal areas of females and males.
As sarcoids of equine and genital warts of humans are normally transmitted by different means, are caused by different viruses, occur most frequently on different parts of the body and are found on different animal species, it does not appear that any significant relation exists between these two ailments. Although the 3M Pharmaceuticals imiquimod 5% cream was reported to have been tested on laboratory animals and that it demonstrated antiviral, antitumor and adjuvant activity, heretofore it has not been applied to equine nor was it developed to treat any equine disease.